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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb786ff0b0ee482fc5ea98e8a71068b6d6b188ee7d7d400cb679c7fd5016f64b' 
  AND token = 'JgmWHI0PLBmrXMHhhQ/FVQcGa8jW1WbapIgLiB2H+Ho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}