SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ddf4351211e116628963c151c3fdfb7fd22cc771fdbc4390d95c3b8e2151888' 
  AND token = 'bjd9bH6dzvAcT6F99TFVK9ibtGLLbrRyyZjZFkNzgl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}