SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd15073598cdd22c1fabf0e99e69678c9a8f665da7b2f3a70b7266369a0df4eb8' 
  AND token = 'K47iEHy+Go5zYfPJxf5XbTDyJpjVmYAc1XG7Kcz94BU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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