SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b6fa494c85520a1bf9f917a4c2d36f6d499163128c2733919262577a319f3fa' 
  AND token = 'bvrj+dgRCGJqa6DGyezlxUiQA+VpREM87p6ooSI3/bg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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