SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90f10d248acde6c06c82f9cc9d50c0a58d1e088b7df9369818308dd868e64a85' 
  AND token = 'zL+nxFa5f/e64wJoSHEKZthxKsMyxHvpncpNXwP3ZNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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