SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02ff8cad6c296f6ec67d52f86db2835f59b0f7e8fa144998619434a5a267d577' 
  AND token = 'a03u3zam/H+RwQRbiUqs1n1XMxQvYhsmA+0A3YhZAUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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