SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf8d6251b07094cfe222dfd5d03c8ab40847aae1b1554aec1e9d643b02f95642' 
  AND token = 'Zx83N2itCbN8M1/4LNDS8ozJTvVw+vVxbwOdy+QPXdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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