SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37ed64fa19a4afe442bde90ee3819da0922aae8a49aff263608589535ec14ad2' 
  AND token = 'ocRpxBdsIcKopPyeHJ4swEXbTmyq+15pM/fY9AbMblM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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