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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c492f679f52df1e38d32b0a1a2de4abf98c52d21bb1b4ce968c73256d9c67b74' 
  AND token = 'LNcyNgBxFmtVXvEs+6q7Yd3CtYi/t6Dyaz5T1AJ8Ypo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}