SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4c56af23f880ad5f8ddf863d407585177a1aaeff66c534a4b88122019a289db' 
  AND token = 'UbYccKvG4XB9J/CpSN4hNJL0JnXxdAnI2+3tCoyH/pQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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