SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '355a5b1dc891d1b800fb2626125eeca6eac6fd8471a5adf649b444713ded510e' 
  AND token = 'pjtSGERdOPWUVxQM+eSeaEcWnCkp813P5Xq9eWqPstc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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