SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd349be876a671eaec72a926857fa8ee11347482826bec864aeb2888840a213ce' 
  AND token = 'f3HfmrdsmMqOPNiMzEsc0PXOhztd4IuEWy81dytd8Sk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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