SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c9a2687763b0a962e9712146eb5584e38cf4b67b89b012ac7994bf91095537d' 
  AND token = 'GC+zYQmgQnTnXXj17qBl4ABXQEICH4tJOuGZELJgyH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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