SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6f63b11a28b329cfe594db06e8f657dbb9ce13032f1cbb93ac64866e715bded' 
  AND token = 'Ri+7HWJMrn4NXSwUGtpOSHg8U9iPklDxsdXYGrPCQ2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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