SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48b6fe97370e52e999f36a7cf7c66087fd57bc115e4bbf14a859ddbde3d42973' 
  AND token = 'x7Rgm+xbs9jWlsyFasxHRdZgVGHWXKLP7oILu4ZwL5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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