SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ee6ce49608c77b7a7f213938b61c9a1c47faf1d319f319b54a887401d79fe2f' 
  AND token = 'z/DypKQ22lGbiJastYspLYdDqu6F/YNTAvcXTuAQibI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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