SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd0878add74afbc47fe6aa12c0fa5b9ec357fd3e9ff8ef1845f90f63a5b3623d' 
  AND token = 'zwg4CzhMe1JCCx/fJ4HZs44Olm5tV8MQBhjh44Bjm6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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