SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdef4355d7611defc2e3633d823819b8e8bd23e1c445e166608697714615b49c' 
  AND token = 'IKDCOUzvxgH8IvtckvzFUoLzrY2a3EndJSru/ZNK4fw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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