SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '247485389d5dbe00fc51f8f9d1e7fafff9600c4b84b57c48dac037332434e0f0' 
  AND token = 'rH+XJecd2sPp3gOrSvICtXos+1ZilThHIKoaEccQaC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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