SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '384c7352879fce457edf49531d386166bd38acb113847145cd0f375bdca3e681' 
  AND token = 'j/h9N2UTSqzZYC2S0oEvwhAckjO2+F/Z0ICvII6CfUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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