SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04feb62067e6a32027bff8231d7bd56a0186f38e7afd137b61c42807971e97f1' 
  AND token = 'u3GPD2u1ULCSrErcNKDSYnTXhmziHZ8H0EVKKEPnZvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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