SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d5c6f9e0f2c8d2c6d4fee17449ed7e22c7febdb99f8d953f60679da9b99ab44' 
  AND token = 'SLgV/WKh8Mlj3vhHr2p3PyhYl0/uBguSkgZLtYAqD2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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