SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84127338f6b82a8e7236ecd385d5f56c49d6a5683d12709f7902af3e33593092' 
  AND token = 'nMDl2jGTmBBS7RNiuJ1ll/6ElUwD+pJ+CZX6mlyv76U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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