SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '90a25519dbce8b000792b1d4f36d295bcfeee883da8642d8fbbb0757e00614fa' 
  AND token = 'k4yYIGjFxi66ZCSk/iKDGEt09rX8+GmpB0JXyAuHwrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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