SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '960838636aacc1ca7bcb8877c96009dfe70689943fd6cf479841648aa52b941e' 
  AND token = 'kLJDGzj4SwFiGu3e3rAcjuIVjXrZtskw8WXHujIZ4WU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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