SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0df158a3cbc25be4ffc7670b9bb1abfe16e0512fdac9e15db5c475045a2a418f' 
  AND token = 'AtcxWEDpfUvOrcGnXj2fUFrBA4F2n+0EpXEvMG9lp+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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