SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29c66597151a29e3ec2b566c004fbe9f50a9935a7aae78f2fccdf2d4af7bad91' 
  AND token = 'O8q2rjFz8C3nEVBIw51fa7Z7woyMB/oBVKxY8UElBSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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