SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53c0074416d55deb4a80ac6670e34ccef6807fbafb9b2e0ce72834075551a143' 
  AND token = 'ID2FSzDTZTXJcg1Rsai9Bmo+VWL2UYAhQm/+Bi9v7PU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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