SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '593e07fa3e2508359a203b46b946e87fcf6e348266875d9db9d8b953fbd31c07' 
  AND token = '9YlBAEO6Z/XjJXQPCVtTnoeWgNicD2LZGUl1JQ+dAwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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