SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3b11f16afafd5384a41db7b06fc9edbe7be8decc507a7209152803bc02444ff' 
  AND token = 'IWld6Ueb/biyVkqh6HmKa8YNOi+VCrlnBfHBUxFucWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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