SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b2bd6a74f8599431968c3a510a1e1e33ad56da2a6a7240e86167e12a93ab94fb' 
  AND token = '6JK9H5jc1Dsms9EOY2qnv/ITKskchs1oMduBRZGS4e4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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