SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abdb17da2bbe8bd24b6d649e55231801e4212db1cd4f7ab3c001c1b261577725' 
  AND token = '/mpEXQPugMJHCkgeGb7uVwhJlmnMZznThjVwz0lWrOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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