SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '51a534f8efa2dd85784415a0de43ef4503d069973f8b8401bf6ca7573a7cfa67' 
  AND token = 'i1gjdqtbA0Tw3jW5GTVrJJfcnDS86cvI/CA8wiKp6pA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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