SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fedc05e7eda96b6455dd44525216681023a6aa5ecf2b1f367ec9c8b67706c41' 
  AND token = 'l55prquDZRtdazPvkkTrUsRUGSYfhkQlkEIpvVemYhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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