SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9de58b1ec454bc2428bdacc806bb9544b32eb215c3dc2f913bf571e0f300c614' 
  AND token = 'KOkkU0zikD9mcbDWAbIj15Wr0vHr8LFzuu9JV8g+9K4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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