SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a76cb08fa835c2c6c297e7d427b0d5a75dda9ad4aa2200d2a5059448cc45f37' 
  AND token = '8PwEXbb8prx69Zm/MMVajx7LtNvkrT+EHE+XcQqdvBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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