SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bee38c914bf7f92fd4af33dae749b0672c7026bfeea4bf5231ec6c21e5838364' 
  AND token = 'rSkeWTohdXKuFRSBHmid+dsmeLuYaJTARrE+YWAnKwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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