SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10f483559b68a9487733bdad3d393bbc6f0712da681c183b1682a9d770a2eaff' 
  AND token = 'LT81OK+T90fm9IQ73wKAwRh/ZuttRqsYp2UGe+xE9KE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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