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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '251d5657d12b823b5193a04d915418f5ea1f089db7381bed549101773feafa3b' 
  AND token = '165fjxjd/eT9Ffg04CS9bnwzTyPldcdGPbGq17bQ0O0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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