SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16bf024f5b6784349333c732285ec809a388b5ff25c6075f0fec954c7e17545f' 
  AND token = 'B398VEJg+Nq4605R4uVksmPvHXeuTLCuApHR9xRT7Q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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