SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '681ea36b648662579930effb32697870efbf5bac59485e6f4cdf3f2e7b6fc333' 
  AND token = 'bJDvfB4MaL4M7RGgd34yKQRlia++hiILAsUpFrgH5Ik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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