SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b969a01eb37ff210943f92b46e987793d51954397b74f91e6305a0ce4021f8b' 
  AND token = 'GtTvyU70RGfwpQMNvwQMl05Z+JXBZj8PaERhSJ5FJqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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