SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48c9b796288fcba68091ef31f5f5940bf643ce4ad08f3e9ce5f3bc94a06d64a4' 
  AND token = 'AWRzGOrU/pBKb+IdbtmGyYRVQaSYY+Vez2+4D+IBq2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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