SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8f41023f80df6e02d2285fff0a49f868dff7ef4c470230d90069472dbdf11ef1' 
  AND token = 'umEVgeTv/1hQGE/JhyW9PKza/PWfNAOn3nKYVwTelgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}