SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08c8e277c4d600dbbd38e05ff95d3fa22047aa4cf7b2ec35bd123b1998b15476' 
  AND token = '6X4FgIX0vEaD5qMUrbz4EuC8sWUNcnvCwiF0CTOHmxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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