SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ddb28163df8c6479e04af3110f1ec80fe8e732caef92445313d9ae4f37de671' 
  AND token = 'qmNr/Sa1C2EVDPnbMCmMGpc4jjlgsbTzznHwbqJtgZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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