SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a13ada5532b49602cb55bb7f8786de529391731124155c4ed6177af34885ea89' 
  AND token = 'KsKS84vapaexcyMzZdDtbaMYueYuZD+WEbSGQH2k4Vk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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