SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8de6110d4b01763abe1a3228c3246f5b5cd78331c7c748130775e94c6396256e' 
  AND token = 'EiXl09D9ghQKvCvRZDmPg4yLPMX9SbmWsU8YjAvp420=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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