SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e685df198d523f5f894c2629cbed3ff1a8c14e834a017a8045d67895f23a8c9e' 
  AND token = 'kv2RGFQfw17uj7SBdXvOJuIU4QCuKxjb0usfn+YM9mM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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