SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '090fd8a3c896456d4d012e0241c0315cbe920c21c61eab0b35313e09a3330972' 
  AND token = 'B7sMcHHGvTZ0VfduTqaBxmMDfT0pAXnVRrYJ8S1ycn4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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