SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd55f189af434e8b4ab4ee4cf9f39ef7aaaaba06ee3a65de6c2de711b293a7648' 
  AND token = 'U1xdDujGf2kpRkfIQ6iPQtTJpCWCBBTlWAb0T2jAip4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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