SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c28182ac438d3d09e1e35f39e8c31edc90985e38fe80f578fe8330f91c16916' 
  AND token = 'zm62t9jAP6VKet3eiKfgCbAdye1QpLXOJRA4XkyIcAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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