SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f58601f2587148ee3ae4f677cbb3b345a2589c2ad7dbdedb25504394b5499572' 
  AND token = '96VkancnX41ieAm016+lpoayEjYgB9nNndphff5MbeM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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