SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc208a103ad8f9b3311075bfd5dc7b5d4d68a10c3ada80eea1eb6a81f9b31642' 
  AND token = 'RBnCGjfDqIGIS477AAdR/yXhAA13cOEZKh4OaaOXILI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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