SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a7aa4196726b2a1ea5114e47a1b9eb7b450de7bc77711dbe10c8f28b462691f' 
  AND token = 'n/oPfLGRE8lIVY7ujgOhIMlJaiZAIAfihQbK5iQLUF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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