SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b92d7f4ce13cb6ac213f0489e2cbe04b84425f7ef0628bef6cf60d52b49fd0e' 
  AND token = 'YOFUMMZAjzvZGlI2kZfsDabXhAJzJNnbYHfeiam0RO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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