SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb26a340c3baf073c6db0948940b446caba3c1d354f89502f60086ce3dfcc6c4' 
  AND token = 'E0XLpMsyn0hBr2qowRU3m2REUPy4IJSsxOQ0Fvws9ps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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