SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96f1feee91da4df0b4da710f8904dd8c41cd53b7d631466a07ace299c747890b' 
  AND token = 'Y8ame6CfMRpaqMrfEjtgrvRvwCBP2gVc/CNfXGMpp1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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