SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '17df7b403d7265bc2f3296fdeb2273d189a6890d5c44073fc31d1993f4ad0a7a' 
  AND token = 'S7XxtyoCS3a9M/h5ieM4Z7EmDgeT8/vAr+zd/82XEZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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