SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '620f3360ff1a5d311e8bb566d0a2220aebe6b5e77c53e17357935698ab1c4209' 
  AND token = 'm3UTYNasRACSbJxRP5dXczxW6TllwhUz3J5GF/3+7WM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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