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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08c3e6f75054dd6e01610fcd4af44c24b5825cfc644661189db935a25d2ee127' 
  AND token = 'pbkkVtYCJtWZ1CQeOxDaXBpQoWT9VwXLqcCLzLaes7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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