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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6ef6df4734ed673eacd287e2e276cf3a88a6577ea5d16379bc7fa19ddbabb3c' 
  AND token = 'iVD8LUVxx1UFYe+5uWiYEi/P7S1tkbIFJFHbqwzvEA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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