SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1573866b415c1dc351ff78fe9bd38a899e1506132e2c06c326c17607b442571' 
  AND token = 'Dz3BQ8dnPnN2EjZVjwZMddJphxmOswq6F4mY6W2aR34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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