SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfbee935a17a88d17e81a906fc342fee9f84da44257fe3212a5f07cc61213f7e' 
  AND token = 'gQBKmhpbCy3oqzCJgW8DR+TCX10+uKzKi+orXR9Hg6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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