SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '13a53d2faee6223a97c40dd9469d9e14a3d8a5421988bf9edcb1314d46a617f0' 
  AND token = 'WZr6LHumTZN5EUm8ZfJuiGCDJdeWbgtjdMEJ4Zfl+bY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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