SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '268687eee4ff8a92934119aa23b1376ee80c65139152a0608df1cb84b512d853' 
  AND token = 'Z6cBtTs1LdSKaX786YdAlED/qQHTQI0DmITPe5r109g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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