SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c83533a9240793b4ddffea8fd55381fb3cb86389961893cb46be7f449c51bc0' 
  AND token = '7fR9aSAuMLgLstd7txWcxrARJ8OrgMsW4zTzSUyEN/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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