SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7eb48abb2fa4f759ca1204d80b704d57d7b3870b915632def1bb7cc639a26d86' 
  AND token = 't0Ckao3xl6I4wMugLhMjYj2a/pkM9mGYP6+iAqKbNqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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