SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '54ded2ebbdfe9737b2db044d14c6145b55a7cdcee7e8a2fc041c4bb0797a98f7' 
  AND token = 'L+XEpP1w84U/7WHVOCPAWMTjDe1iqrRhfYUVxdPIg34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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