SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '530d832452589a486d19f854c02f7bdf693bc72a81863a3077893883675261af' 
  AND token = 'op3i/2ILGkqPgCnJ6HrODXk4VpHywrroaPEiVwv29BM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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