SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63aa7103613e1d02602489495b193c62062b954218ac7c60d60a0a15a139187a' 
  AND token = 'IVEBpgrZZuLdCt49zzTBIqk0K/VW7vRa31rFpBcV1nA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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