SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fb9fede467ac4d403cc392475c81fd58d55b393522468b1ee2c458478cdf04b' 
  AND token = 'KJ/etNKhT8Df33cV6bFWeTUVtpiIZZqWKI+/b0uS684=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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