SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b8ccd0ca3123bea0d09f0fcc911f2a21ad0357e3c521708f5baeb4e84ab03f5' 
  AND token = 'bpiZBYQouUCepODyf0NubQMhP8SLJ1B/VmMnjgcx9AI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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