SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8052d9d3f31e673214ced8e5196274581c21f7d6558874b5299358441262edf' 
  AND token = '+6CuV2V35uW4qFV1Fe+GDXSOaURB0BJ1pOzNzTFhP7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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