SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4e1881fdf76c02b0249c9555e0f45e7d007da88f2b9adf87fc590fc806c3ed23' 
  AND token = 'JDMazLgBfAHd9eEo1T5ZtCT+MFuXbrbjboNhdpvXtew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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