SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f645ba9f982e7d037f206f0848a76cc517fb21809e96a0da0868b69d4d6105c' 
  AND token = 'Rr4OJuTkiei1THQOY/pigJgS14qdDTi8OiYRTAkFY2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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