SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ea57154012d54325948004569f8936c6eedd7648eae5ca717e6533f2e7c5d6a' 
  AND token = 'dMis9RQ40BWnpUjrzmZih5Hbzh2iZzRd6Dw8Wg0BGcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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