SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7398eed7fd5c4e7fdee69b076278442123f35c58c307ef5892a915d3676086d' 
  AND token = 'VZ+vR3LZLXeh4FVhCBaw+Qv6uY8ekVUEvcQDVIJNyw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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