SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '501ccfe3afdc2fce9aa7df141d9a99f3ee067fc93270ca929ef1e37ebae3867b' 
  AND token = 'pbD7gBZpbYRkwCgqE+SB4ZJB+sFNrs7mmAKu3NKBGwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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