SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3acadc4489f0877b05cf3d9a7ba9c412214b0dfc9793246955a655bfb84ffe66' 
  AND token = '5mnuStAvo3KXKmA1x/ZYPTnSlu2UZVEsktST8qpbrGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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