SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6e2e7d4c50f2b3f68112f04aa728b25be73928b7d0a12966363ae888b5d8f922' 
  AND token = '/jwQqolIfS6pZlju6RBbN64pkKgNyt+fw1g+03tGeQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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