SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '190b2929cac068e067f56f32aff0a784e6aad453331c76626b24907dff5fade9' 
  AND token = '6whRl9rnqMFGIfIOvSBlMJX0l1vIGN8M4qC+2W9gTBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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