SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '272279ca3e6d7d4823d9e9c0039fa92a1516a6d672746df848e55336bd7004bb' 
  AND token = '3GYtpPRo1ABnm9e8vTUF605QxjGUaKDQhCLW+4tOyJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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