SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efaa1a93ebd16865cdaf51af474c2fee7a286aee246ca1accc204dd3ef89f286' 
  AND token = 'joTiVXKtUI9gc7qwPbs+kkHKnvHLW/rJwkj5RaK3pMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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