SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a62d33bef2416fe22dad11655f180c48ce1da00135197c5d60ee41754627522' 
  AND token = '6xl0/CMPKoWnXShMkkmLII9AmuAI4nV5iVFAPplGPGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}