SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55b591da2f216e9b137915ff9cd112db7416e5f0da3cc92678cb986d94d5fe39' 
  AND token = '8GvXM4FThWYYMsJ9UdNGVsnNq2PY/Be2wlNYWrkyOzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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