SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b300049a98a851601bb93fee8aef8805da9466e5420a060e419974cb9ae37d78' 
  AND token = 'bXIzW4dn/9hSrNgd0Ttu6Hz2J8IoVAidyXApxqAQPgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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