SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f8409151ec3b80eee8ddd1b6f4f64419c0b37a0824c03d18ff3d99c5b092083' 
  AND token = 'AHgD+jZAd5PY1sLqZcuNtQbEwyJKK1SfMpjjdUM21GM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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