SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce05e3d3a897f8e16fcdfcb804a9e4799988f9c8530d4a6bf7d3dbf9d2e2c6e9' 
  AND token = 'AvXGkJfa1gvK8RLDjKq4+XKoh0qNJwQDDuFX0Psnaz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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