SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdce081398d8b38134a57612989e6014a881bc9b33b12799bb1dd942a9a92a8d' 
  AND token = 'RrPIioaduWoFpWUrsPtHzKJhUzZMxHOk4PZZvxMl6As=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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