SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40391e028f20a6902fb0e0b03ae744e8864f7f70a9200f1399c583d5b6782b32' 
  AND token = 'Vm+Ip3sCFwVoxyWljUFjTIqz0/1dPni4spfK2rhchXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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