SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '027b165399237a3c0973046ae971852fda5b9c7dc4e22c14a9ef78d9206e46d8' 
  AND token = 'hcjCr8DbRQAwvKmQJVioHlV86TgoH4zUz+yvg5eT1Y4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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