SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb235ab789139700c657f60c3cdcf604411b741715664f02c35def58daf5f5bd' 
  AND token = 'hIdkSg8aSQz+pwnxEOfVZ8/KKqPAGlMY9jZ9uvpXfak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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