SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '77c3738233f1e86de4e809552cfc49fb22c3eb75da63233e7a95d0a1a5a61e48' 
  AND token = 'Mi/QByRufI4PppjxBxLZP+Crl9c5WkoDFtwez/EKiGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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